Window lights are commonly placed in apertures in doors and secured by trim frames that overlap the periphery of the aperture on each side of the door. The trim frames are typically retained in the aperture by screws or other mechanical fasting mechanisms that connect the frames placed on opposite sides of the door. For example, see U.S. Pat. No. 5,941,032 issued to Lydon, Jr. and U.S. Pat. No. 7,086,206 issued to Wang, et al.
After such trim frames are secured in an aperture a glass pane (window light) is inserted in the opening in the frame and then secured in the frame with a glazing bead.
Such frames which abut on the exterior surfaces of the door in part, are exposed to external elements and, in the case of a fire door, to conflagration on one side or the other side of door. When made of plastic such frames fail when exposed to fire and the window light will be displaced enabling fire gases to pass through the aperture in the door when such lights are used in a fire door.
Further fire doors are rated according to standard test methods, such as ASTM E-152, UL 10(b) or NFPA 252. It measures the ability of a door to remain in an opening during a fire to retard the passage of the fire for determining the fire resistant properties of the door. In conducting such tests, doors are mounted in an opening of a fire proof wall after which one side of the door is exposed to a predetermined range of temperatures over a predetermined period of time, followed by the application of a high pressure hose stream that causes the door to erode and provides a thermal shock to the door.
Thus, unless the window light is properly secured in the aperture in such a door, which light is conventionally a glass pane with the imbedded wire mesh in fire doors, a stream of water will blow out the window light. Alternatively if the frame melts, the widow light may simply fall out of the aperture, if the frame is not made of metal. If the frame is made of metal it conducts heat to the window light causing it to crack and also can conduct heat to the components of the door leading to a premature failure of the door structure itself, particularly if it is a synthetic door.
From the foregoing it will be apparent that the glass pane must be properly secured in the aperture of a door to achieve fire retardation. When properly secure secured the aperture without depending on a typical trim frame, any thermal barrier provided by the frame and/or the trim around the window light is of secondary concern, allowing the frame/trim to be selected for aesthetic characteristics instead of its fire retention properties.
Metal frames have been used for fire door windows and have been painted to match or simulate wood but are not wholly satisfactory from an aesthetic standpoint. U.S. Pat. No. 4,637,182 issued to Ellsworth et al discloses a framing or trimming system wherein “bead strips” of an incombustible mineral material are provided with a wood veneer bonded thereto. The window pane is held in position by a plurality of small clips and associated nails which extend into an incombustible core of the fire door. See also U.S. Pat. No. 4,930,276 issued to Bawa, et al and U.S. Pat. No. 2,927,353 issued to Snikter, et al addressing the problems of retaining window lights in fire doors.
It is an object of this invention to provide an improved glazing cleat that will retain a window light in an aperture in a synthetic door, or other door like structures, when the door is subjected to fire (to a degree) and/or other similar physically challenging environment conditions.
Another object is the provision of novel glazing cleats with a low profile that can be easily hidden by an exterior frame around the periphery of an aperture in which the window light is installed and retained by the cleats.
A further object is the provision of a novel glazing cleat which can be used with conventional synthetic doors, such as those disclosed in U.S. Pat. No. 3,950,894 issued to DiMaio and in U.S. Pat. No. 4,550,540 issued to Thorn, which are widely used in the interior and exteriors of personal living spaces or workspaces because of their aesthetically pleasing surfaces. Reference is made to the construction of such synthetic doors disclosed in these patents as part of the disclosure herein.
It is also an object to provide a glazing cleat which allows the window light to be closely fitted in the aperture so that the light can be sealed in the aperture to prevent or limit hot gases from passing between the periphery of the light and the aperture.
A further object is the provision of a novel glazing cleat that cooperates with the skins used to form the door whereby a window light in an aperture in the door is mainly supported on such skins.